It is typically the case that an optical signal transported over an optical fiber must be coupled between that optical fiber and another optical fiber or an optoelectronic device. Typically, the end of the optical fiber is outfitted with an optical connector of a given form factor, which connector can be coupled to a mating optical connector of the same form factor that is outfitted on the other fiber (or optoelectronic device).
Optical cables that are connected to each other through a pair of mating connectors may comprise a single optical fiber. However, more and more commonly, optical cables contain a plurality of optical fibers (sometimes more than 1,000 fibers) and the light in each optical fiber in the cable is coupled through a pair of mating connectors to a corresponding optical fiber in another cable.
Optical connectors generally must be fabricated extremely precisely to ensure that as much light as possible is transmitted through the mating connectors so as to minimize signal loss during transmission. In a typical optical fiber, the light is generally contained only within the core of the fiber, which typically may be about 10 microns in diameter for a single-mode fiber or about 50 microns in diameter for a multi-mode fiber. Accordingly, lateral alignment of the fibers in one connector with the fibers in the other connector must be very precise.
Many different connectors are available on the market today, each having a unique form factor. Well known standard optical connectors available today include MT, MPO, SC, FC, ST, LC, and SMC connectors.
Commonly, an optical connector comprises a ferrule (within which the fibers are laid out with their end faces coplanar) enclosed within a connector housing. The connector housing usually provides coarse alignment of the ferrules with each other as well as a releasable latching mechanism for holding two such mated connectors together. The ferrules provide the fine alignment of the fibers, often within tolerances as small as 1-2 microns or less.
In some connectors, there are two forms of the connector, e.g., male and female, and one such form can be mated only to the other such form. In other connectors, known as hermaphroditic connectors, there is only one connector form such that two identical connectors can be mated together.